High-concentrate masterbatches comprised of multifunctional compounds for polyester expanding process

Abstract

The composition and the preparation of multifunctional high-concentrate masterbatches for production of expanded materials of aromatic polyesters are disclosed in this invention. The masterbatch includes a thermoplastic wax having a vicat softening temperature not higher than 100° C. and a high-percentage of a multifunctional compound, wherein the preparation involves a) a low temperature process with a masterbatch temperature lower than 100° C. before cooling and b) cooling without contact of the mixture with water during the whole process. The high-concentrate masterbatch can be applied in production of expanded materials of polyester.

1 . A high-concentrate masterbatch comprising 2-20wt % of a thermoplastic wax having a vicat softening temperature not higher than 100° C. (A50 (50° C./h 10N), according to ISO 306) and a multifunctional compound selected from one or a mixture of tetracarboxylic dianhydride, polyepoxides, oxazolines, oxazines, acyllactams and sterically hindered phenolic antioxidant, wherein the masterbatch is obtainable by a process which is characterized by a) a low temperature process leading to a masterbatch temperature lower than melting points of said multifunctional compound before cooling and b) cooling without contact of the mixture with water during the whole process. 
     
     
         2 . The masterbatch according to  claim 1  further comprising high-temperature thermoplastic resins, preferably in an amount of 10 to 85 weight percent, particularly preferably 30 to 60 weight percent of the masterbatch, and selected from one of thermoplastic resins or mixtures thereof having 1) a melting point not lower than 200° C. for crystalline polymer or 2) a glass transition temperature not lower than 140° C. for amorphous polymers. 
     
     
         3 . The masterbatch according to  claim 1  comprising a thermoplastic wax preferably selected from one or a mixture of acrylic polymers, vinyl acetate polymers and polyolefins. 
     
     
         4 . The masterbatch according to  claim 3 , wherein the acrylic polymers are preferably an ethylene-acrylate copolymer selected from ethylene butyl acrylate (EBA), ethylene ethyl acrylate (EEA), ethylene methyl acrylate (EMA), ethylene/acrylic ester/maleic anhydride terpolymer (EEAMA) or a mixture thereof. 
     
     
         5 . The masterbatch according to  claim 4 , wherein the ethylene-acrylate copolymer contains 3 to 50 percent of acrylate content by weight of the ethylene-acrylate copolymer and has a melt flow index from 0.1 to 200 g/10 min. at 190° C./2.16 kg. 
     
     
         6 . The masterbatch according to  claim 3 , wherein the vinyl acetate polymers are preferably an ethylene vinyl acetate copolymer having 3 to 50 percent of vinyl acetate content by weight of the ethylene vinyl acetate copolymer and a melt flow index from 0.1 to 200 g/10 min. at 190° C./2.16 kg. 
     
     
         7 . The masterbatch according to  claim 3 , wherein the polyolefins are preferably a polyethylene having a melt flow index from 0.1 to 200g/10 min. at 190° C./2.16 kg. 
     
     
         8 . The masterbatch according to  claim 1  comprising the multifunctional compound preferably selected from a tetracarboxylic dianhydride with 2 or more acid anhydride groups per molecule. 
     
     
         9 . The masterbatch according to  claim 8 , wherein the tetracarboxylic dianhydride is most preferably a pyromellitic dianhydride (PMDA), in an amount of 5 to 98 percent, preferably 15 to 95 percent by weight of the masterbatch. 
     
     
         10 . The masterbatch according to  claim 8  further comprising 2 to 40 weight percent, preferably 5 to 35 weight percent of a sterically hindered phenolic antioxidant. 
     
     
         11 . The masterbatch according to  claim 10  further comprising 2 to 40 weight percent, preferably 5 to 35 weight percent of an oxazoline. 
     
     
         12 . The masterbatch according to  claim 10 , wherein the sterically hindered phenolic antioxidant is calcium bis(monoethyl(3,5-di-tert-butyl-4-hydroxylbenzyl)phosphonate) or 4-(3,5-bis((4-hydroxy-3,5-ditert-butyl-phenyl)methyl)-2,4,6-trimethyl-phenyl)methyl)-2,6-ditert-butyl-phenol. 
     
     
         13 . The masterbatch according to  claim 11 , wherein the oxazoline is a monooxazoline or bisoxazoline or trioxazoline or a mixture thereof, the particularly preferred bisoxazoline being selected from
 a. 1,3-phenyl bisoxazoline (1,3-PBO) and   b. 1,4-phenyl bisoxazoline (1,4 PBO).   
     
     
         14 . The masterbatch according to  claim 2 , wherein the high-temperature thermoplastic resins are preferably polyesters or compatible to polyesters, particularly preferably selected from PET, PBT or PEN having an intrinsic viscosity of 0.4 to 1.4 dl/g. 
     
     
         15 . The masterbatch according to  claim 1  further comprising a thermal and/or process stabilizer selected from a secondary (preventive) antioxidant or a mixture of the secondary antioxidant and sterically hindered phenols. 
     
     
         16 . A process for the preparation of the masterbatch according to  claim 1 , wherein the thermoplastic wax and the multifunctional compound all in form of powders are homogeneously mixed in a mixer and compact-pelleted to granules by using a pan grinding press, whereas the compacted mixture has a temperature of 40-110° C. before cooling. 
     
     
         17 . The process for the preparation of the masterbatch according to  claim 16 , wherein the mixture out of the pan grinding press is continuously cooled in a vibrating cooling line tempered at a temperature of or below 30° C., whereas the granulated mixture has no direct contact with water. 
     
     
         18 . An expanding process for production of an expanded material comprised of aromatic polyesters by applying the masterbatch of  claim 1  in an amount from 0.1 to 10%, preferably between 0.2 and 4% by weight of the mixture, wherein the polyester resins to be processed are selected from a group consisting of virgin, post-consumer, recycled resin or a mixture thereof in form of granules, agglomerates, powders or flakes. 
     
     
         19 . An expanded material, preferably a foamed cellular material obtainable according to the process of  claim 18 . 
     
     
         20 . Articles containing the expanded material of  claim 19 .